Polyblend gems and the like and methods for producing them

ABSTRACT

The disclosure shows, among other things, a cabachoncut chatoyant gem made from fused and aligned polyblend filaments.

United States Patent 11 1 1111 3,762,976

Wincklhofer et al. l l Oct. 2, 1973 l l POLYBLENI) GEMS AND THE LIKE AND[56] References Cited METHODS FOR PRODUCING THEM UNITED STATES PATENTS 1lnvmdrsl Rbbmcl wiicklhofer; Gene 3,639,195 2/1972 Sanders 156/306Weedon, both of Richmond. Va. 3,369,057 2/l968 Twilley 260/857 I v3,148,102 9/1964 Eakins et al. 156/161 [73 l Asslgnee: Allied ChemicalCorporation. N w 3,544,406 12 1970 McAllister 156 174 YOlk. N.Y.3,623,928 11/1971 Wincklhofer 156/175 [22] Flled: 1971 PrimaryExaminer-Daniel J. Fritsch [21] Appl. No.: 117,141 Attorney-Luther A.Marsh Related [1.5. Application Data [62] Division of Set. N0. 725,767,May 1, i968, Pat. N0. [57] ABSTRACT 5 The disclosure shows, among otherthings, a cabachoncut chatoyant gem made from fused and aligned poly- 52us. c1 156/173, 156/175, 156/180, blend fil 156/250, 156/296, 156/306[51] Int. Cl B32b 31/02, B32b 31/18 [58] Field of Search 156/154, 161,166, 2 Claims, 5 Drawing Figures PULYBLEND GEMS AND THE LIKE AND METHODS1 R IPRDDUQHNG THEM This is a division of application Ser. No. 725,767,filed May 1, 1968, now U.S. Pat. No. 3,581,522.

BACKGROUND OF THE lNVENTION 1. Field of the invention The presentinvention relates to a gem and other similar objects and to the methodsof making them from polyblend fibers made from at least two differentpolymers having different indices of refraction and different meltingtemperatures, with the higher melting temperature material present assmall fibrils dispersed in a matrix of the lower melting point polymer.in order to make the gems and other ornamental objects, the filamentsare fused together in a mass and formed to the desired shape. Afterpolishing, the resulting article has a silky sheen if the fibers arefused together in a random fashion, a chatoyant sheen if the fibers arefused together in an aligned fashion, and shaped similar to a cabachonand exhibit asterism if the fibers are aligned parallel to the side of ahexagon or other polygon prior to fusion.

2. Description of the Prior Art Heretofore, gems and similar ornamentalobjects have been made by taking thin, sheet-like piees ofureaformaldehyde broken into small pieces and mixing them with granulesof a synthetic resin such as methyl methacrylate, for example, andmolding this mixture under sufficient heating pressure to plasticize thesynthetic. resin without plasticizing the pieces of solids. Also, priorto this invention, gems and similar ornamentalobjects have been madefrom clear polymers having suspended therein birefringent material.Patents showing this prior art as well as other examples are Conner U.S.Pat. No. 2,353,995 and Boone U.S. Pat. No. 2,663,171.

SUMMARY OF THE lNVENTlON In accordance with the present invention, aunique new article having ornamental value, especially in thepreparation of gems, and the method for producing such an article hasbeen made. The starting material for making the article is a polymerfilament of the type shown in Twilley U.S. Pat. No. 3,369,057 issued onFeb. 13, 1968. The teachings in this patent are incorporated herein byreference and show a filament made from two different polymers, one ofwhich forms a matrix having a lower melting point than fibrils of adifferent polymer distributed throughout the filament and having theprincipal axis of the fibrils oriented primarily parallel to the axis ofthe filament. The fibrils, which may be a polyester as shown in theTwilley patent, also have a different index of refraction than the nylonmatrix shown in the Twilley patent.

A large number of these filaments are oriented substantially parallel toone another either by winding on a mandrel or pulling through a die andusing suitable heat and pressure to the extent necessary to cause thefilaments to fuse to one another at the fusion point of the matrixwithout the orientation of the fibrils being destroyed. These fibrils,incidentally, have an order of magnitude approximating that of visiblelight. For example, the filaments of the Twilley patent have fibrilswhose average diameter is usually not above one micron and preferablynot above 0.5 microns, although the length on the average is at leastfive times and usually at least twenty times longer than the averagediameter and typically average a length of 250 times the averagediameter. This is to be contrasted with the wave lengths of visiblelight which extend from about 0.4 microns for the extreme violet to 0.72microns for the deep red. By taking a section of these fused filamentsand grinding and polishing them into a hemispherical shape, called acabachon by lapidaries, with the filaments and fibrils orientedsubstantially parallel to the base, an article is formed which will pickup and reflect light in a manner to afford a single streak referred toas cats eye or chatoyancy in certain natural gems which exhibit asimilar phenomenon. While the exact scientific explanation for thisphenomenon is not known, it is theorized, without being bound thereby,that the chatoyancy is due to the fibrils being oriented primarily in asingle direction acting as transparent or translucent inclusions with adifferent index of refraction than the transparent matrix, with thediameter being of the order of magnitude of the wave length of light,whereas the length is substantially longer than the wave length oflight. If we are not talking about quantum effects, there is no suchthing as a ray of light. A ray simply represents the direction alongwhich part of a wave front is advancing. An analysis of the behavior oflight as an electromagnetic wave shows that the fundamental processes ofrefraction, reflection and scattering between two interfacing materialshaving different indices of refraction are not at all simple when one ofthe materials has a dimension of this order of magnitude and whenadjacent fibrils may be spaced at comparable dimensions. Instead ofbouncing off the interface between the two media, a wave train actuallypenetrates the second medium for a short distance before turning backinto the original material. Light conduction lengthwise of the fibrilscomes to resemble the transmission of microwaves by wave guides withmost of the energy traveling down the fibril along the outside ratherthan inside the fibril in such a manner that a single streak of lightperpendicular to the direction of the fibrils manifests itself in acabachon-cut.

Also, ornamental surfaces can be prepared using this material in anon-oriented manner to display a silky sheen with numerous reflections.This is useful and moldable in itself as a new ornamental article eventhough it does not have the dramatic effect of the cats eye.

if the filaments before being fused are laid in a manner that they areaparallel parallel the sides of a square, hexagon or octagonal prism,then asterism with four, six or eight points on the star will bemanifested. Similarly, other polygonal shapes such as a pentagonal prismmay be used to create a five-pointed star.

Also, the ornamental object produced can mereby be used as one componentin producing a gem or other object which is made up of several layersutilizing other materials therewith. Also, the fineness and the depth ofthe cats eye can be controlled by the quantity and alignment of theoriginal fibrils or by dissolving out some of the fibrils aftermanufacture.

The jewelry and other objects produced using this material can take onmany forms such as cuff links, tie pins, buttons, decorative ornaments,decorative coatings, and so forth.

Many objects and advantages of the present invention will becomeapparent from the following description taken in conjunction with theaccompanying drawings:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial sectional view ofthe mandrel upon which the filament is wound;

FIG. 2 is a view of FIG. 1 after the filament has been wound thereon;

FIG. 3 is a perspective view of a cube cut from the wound filament ofFIG. 2 and mounted on a dop;

FIG. 4 is a side view of the material of FIG. 3 after it has been groundto a hemispherical shape; and

FIG. 5 is a plan view of FIG. 4 after the hemisphere has been polishedto show the cats eye.

DESCRIPTION OF THE INVENTION As a first example of the practice of theinvention, a filament composed of a polyblend of 70 percent nylon 6 and30 percent of a polyester is extruded and drawn in accordance with theteachings of the Twilley patent with a drawn denier of 840. Thisfilament is then twisted into a yarn to have a denier of 840 and iswound onto an aluminum mandrel in the form of a sheave 8 inches indiameter having a cross-section such as shown in FIG. 1. The depth ofthe groove is one-half inch, the width of the groove at the bottom isone-half inch and the width at the top is three-fourths inch. The yarnis wound onto the sheave by mounting the sheave onto the shaft of avariable speed motor and wrapping 3 to 4 yards of yarn about the centralgroove in order to tighten the yarn onto the sheave. The sheave is thenrotated by adjusting the motor settings so that as the yarn is fed intothe groove the yarn is slightly overlapped on each successive completerotation of the sheave. The yarn is wrapped under suitable tension toprevent yarn slippage. When the sheave groove is completely filled withyarn, additional winding is confined to the center portion of the grooveso that about three-sixteenths inch of wrapped yarn extends beyond theedge of the sheave as shown in FIG. 2. It is unnecessary to tie the endof the yarn to any support member since static electric charges built upduring winding hold the cut end onto the wound bundle. The wound yarn isfused together at a temperature above the melting point of nylon 6 andbelow the melting point of the polyester which is polyethyleneterephthalate. A temperature of 250C. has been found to be suitable. Thetime required for fusion depends upon the size and construction of thesheave, its material of construction and the yarn denier. In the examplejust given, the fusion took place between 30 to 90 minutes exposure at250C. by heating in an oven. The fusion could also be effected by use ofother heat sources such as infra-red lamps and the like. During heatingthe nylon matrix does not melt and flow as might be expected, but ratheris fused into a cohesive mass. During this fusion process the alignmentof the polyester particles is not substantially affected. The net resultis a solid yarn bundle having fibrils widely dispersed therein which arealigned substantially parallel to one another around the annular yarnbundle. The wound sheave is removed from the oven and cooled to a roomtemperature by quenching the assembly in water. Tilting in an air streamcould likewise be used. as well as other means of cooling. The fusedyarn is then cut from the sheave by sawing across the yarn bundle.

A cube five-eighths inch on a side is then cut from this fused yarn andthe side which corresponded to the top layer or outside surface of theyarn is roughened with sandpaper and glued to a V2 inch round wooden dopusing a commercial glue manufactured by Borden Chemical Company known asElmers Glue. The assembly is then allowed to dry for 16 hours and, asshown in FIG. 3, the fibrils run parallel to the left bottom mounted onthe dop. The edges of the cube are rounded by pressing the cube againsta rotating sanding disc preparatory to mounting the dop in a metallathe. After mounting in the lathe, the rounded cube is cut into ahemispherical shape. The rough-cut shape is subsequently polished bymounting the assembly in a rotary drill and rotating the assembly at1700 rpm. The material is polished by successive sandings with 50, I00,200, 300 and 400 grit sandpaper with final polishing being accomplishedby crocus cloth to give the final shape as shown in FIG. 4. The polishedassembly is then placed in boiling water for 30 minutes to facilitatethe removal of the hemisphere from the dop as the Elmers Glue issoftened by the hot water. The finished piece is yellow-ivory in colorand exhibits a bright flashing line perpendicular to the direction ofthe yarn windings as shown in FIG. 5. Gem cuts of this kind with roundedsmooth surfaces are referred to as cabachons.

A second example may be carried out following the procedures set forthfor Example 1, except utilizing a yarn made from 204 filaments twistedinto a 1260 de' nier yarn. The resulting cabachon gem is identical tothat produced by the first example except the cats eye is slightlybroader. This is believed to be due to the fact that the thicker deniermade by the Twilley process produced fibrils slightly larger and givesrise to the observations that the finer the denier of the startingfilament, the finer the line observed in the finished prod- UCIZ.

A third example for practicing the invention is to produce a gem by thefirst example and then remove part of the polyethylene terephthalatefrom the fused yarn byexposure to a 5 percent solution of sodiumhydroxide at l00C. for48 hours followed Ey waterYx traC- tion in ajacketed soxhlet for 36 hours. This procedure removed to percent of thetotal amount of polyethylene terephthalate from the original yarn andproduced a lustrous gem having a greater depth to the cats eye.

A fourth example of carrying out the invention may be accomplished byusing a yarn extruded and drawn from a 75 percent nylon 6 and 25 percentpolyethylene mixture with the filament count being 14 twisted into ayarn of 210 denier and fused in an oven at 220C. for 45 minutes. Thiswould produce a cats eye having a narrow line of light.

As a fifth example, the yarn of example 1 is chopped into short lengthsand compressed between two matched dies made from aluminum to form therough outline of the hemispherical cabachon as shown in FIG. 4. Acompressed material is then heated at 250C. for 45 minutes in an oven,after which it is removed and cooled by a water quench.'The roughhemishpere is glued to the dop, then sanded and polished in the mannerof example 1. The finished piece is yellow-ivory but does not exhibitthe bright, flashing line characteristic of chatoyant or cats eye gems.This is unquestionably clue to the fact that the fibrils are not longeroriented in one principal direction but instead have a randomorientation which gives rise to the silky or milky lustre of the gem.

As a sixth example, a gem is prepared by making a hexagonal prism fromthe fused yarn bundle prepared in accordance with the first example. Sixtriangular prisms five-eighths inch in height and one-half inch on eachside of the triangle are cut from the bundle in such a manner that thefibrils run substantially parallel to one side of the prism, which shallbe referred to as the base side, and intersect the other two sides at asubstantial angle. The fibrils also run substantially parallel to thetop and bottom of the prism. These six prisms are joined together in theform of a hexagonal prism inch high by placing the six members togetherso that the base side to which the fibrils run substantially parallelforms the six outer sides of the prism. These six small triangularprisms are then autogenuously fused together by placing them underpressure sufficient to hold the sides together in the form of thehexagonal prism while raising the temperature to 250C. for 90 minutes.The fused mass is then water quenched, mounted on a dop with the base ofthe prism being the surface glued to the dop and ground to the shape ofa hemispherical cabachon in the same manner set forth in the firstexample. The resulting gem exhibited asterism by displaying severalcross-streaks to produce a sixpointed star. Y

As a seventh example, a fused ring is prepared as in example 1, exceptthat the groove in the aluminum mandrel is three-fourths inch deep inorder to provide a greater depth to the fused ring. After the yarn iswound and fused but prior to being cut from the sheave, l2 equally flatsections are milled on the outer circumference with each of the sectionsbeing 2% inch long. The fused ring is then cut from the sheave along aradial plane passing through the line where the flat faces intersect.Following this, the remainder of the ring is divided by cutting along aradial plane which intersects the line connecting the remaining flatsectors. The cylindrical inner portion is then ground flat in a planeparalleling the previously cut. flat plane. From this blank are cut sixtriangular prisms one-half inch in height and five-eighths inch on eachof the three sides with the aligned axis of the yarn running parallel tothe base of the prism and parallel to one of the sides but intersectingthe other two sides at a substantial angle. These six sections are gluedtogether into a hexagonal prism using Eastman 910 Adhesive manufacturedand sold by the Eastman Kodak Company of Rochester, N.Y. This adhesiveis a methyl-Z-cyanoacrylate. The hexagonal prism is formed from thetriangle in a manner that the filaments run parallel to the base and tothe sides. The assembly is then mounted onto a large wooden dop usingElmers Glue and cut into the form of a hemispherical cabachon. Again, asix-pointed star with each point having a line running through themiddlc of the original triangular section is displayed.

As an eighth example, the process of the immediately preceding exampleis repeated except each triangular section is immersed in formic acidfor 30 minutes. The formic acid penetrates the outer surface of thesection, softening the nylon without disintegrating the fused yarn. Thetriangular sections are assembled as before using a circular clamp tohold them in position. The assembly is allowed to dry overnight. Finalremoval of the formic acid is accomplished by drying the clamped pieces8 hours under vacuum at 80C. The clamp is removed and the hexagon issecured to a wooden dop as previously described and a hemisphericalcabachon is made therefrom. The resulting gem resembles the previouslydescribed gem except the lines formed between the cut edges are finerand less noticeable. An additional advantage of this technique is thatthe adhesive in this gem is dyed to exactly the same depth and shade asthe original material.

As a ninth example, the process of example eight is repeated except thetriangular prisms have two of their sides meeting at a 72 angle with thetwo remaining angles each being 54. The side bounded by the 54 angles isthe one to which the filaments are oriented in parallel planes. Five ofthese triangles are joined together to make a pentagonal prism with theresulting gem exhibiting a five-pointed star. Using the same technique,threepointed, seven-pointed, and other odd-numbered points of stars canbe formed, something never achieved in nature.

As a tenth example, example 1 is repeated except the fibers are bundledparallel to one another rather than wound about a mandrel and sufficientcircumferential pressure is applied thereto to cause them to jointogether as a fused rod when heated to the melting point of the nylon.Gems cut from this material are similar to those of example 1, exceptdue to difficulties in fiber alignment, the cats eye is broader than inthe case of the filaments having more perfect alignment as a result ofbeing wound on the mandrel.

As an eleventh example, example 1 is repeated but using a mandrel thathas a groove with one flat side and the other side forming a series ofsix Aa-inch steps. Each step is in the form of a hexagonal prism inchhigh with each step varying in the base dimension from the bottomportion which is mounted on a iii-inch mandrel to the outer dimensionwhich is approximately 2 inches along the greatest dimension of thehexagon. The yarn is then fused in an oven at 250C. for 3 hours. Theyarn used is the same as in example ll except the filament count is 136wound into a yarn of 840 denier. After fusing the cohesive mass isremoved by the disassembly of the mandrel so as to provide a shellapproximately a inch thick whose outer surface is ground and polishedand a small gem otherwise prepared placed in the inch mandrel hole. Theresulting cabachon is almost 2 inches in diameter at its base and.dramatically displays a six-pointed star. 7

As a twelfth example, example 1 is repeated except only one of thefilaments in the yarn is a polyblend filament of nylon and polyester,the remaining filaments being pure nylon. The resulting gem displays acats eye having a greater depth than that of the first example.

The gems and other ornamental objects produced by the above examples canbe formed in an infinite variety of colors by using the usual dyeingtechniques for the various polymers either when they are in the yarnform prior to being used or else by dyeing or coating subsequent to themanufacture of the finished product. Also, numerous other polymer blendsmay be utilized provided they can be presented in the form of filamentshaving the fine fibrils dispersed in a transparent or translucent matrixwhich polymer fibrils have a higher melting point and a different indexof refraction than the matrix polymer. The index of refraction shouldpreferably be at least about one point difference in the second decimaland the difference in fusion temperatures should be sufficient to fusethe matrix materials of one filament to the matrix materials of anotherfilament without requiring the fusion of the fibrils. In thisconnection, it is to be noted that the nylon used in the invention hadan index of refraction of about 1.53, the polyester had an index ofrefraction of about 1.64 and the polyethylene had an index of refractionsubstantially less than that of the nylon. it was theorized above thatthe light-modifying properties of the article are believed to be due tothe small diameter of the fibrils and their having a different index ofrefraction than the matrix; however, it may be additionally theorizedthat the interface between the filaments where they have been fused toone another may also give rise in varying degrees to the light-modifyingproperties provided by the articles made in the above examples.

The fibrils should be present in the matrix in substantial quantitieswith a diameter not greater than three times the wave length of visiblelight, that is less than about 2.5 microns and, preferably, asubstantial quantity of the fibrils should have a diameter less than thewave length of visible light of 0.72 microns. These fibrils should be atleast microns long.

It is not necessary that the materials prepared in accordance with theexamples herein be furnished merely in the form of hemisphericalcabachons, as other cuts may be utilized or flat, round objects withholes for buttons or flat objects combined with other light-affectingmembers of infinite variety can be produced utilizing the principles ofthis invention which discloses methods and objects giving rise to newpossibilities in lightmodifying materials. Also, it will be apparentthat still other modifications of the materials and products and methodsabove-described may be made in following the general principlesexemplified herein. Therefore, such examples as have been presented areto be regarded as merely illustrative and the invention may be otherwiseembodied and practiced without departing from the nature and spirit ofthe invention and it is to be understood that the invention is notlimited to the details set forth herein except as set forth in theappended claims.

What is claimed is:

l. A method of making an aritificial gem in the shape of a cabachon thatexhibits chatoyancy, comprised of light-transmitting matrix filamentsfused together, said filaments being comprised of a polyamide matrixhaving polyester fibrils dispersed generally parallel in said matrix,which comprises: compressing a mass containing a quantity of polyblendfibers which have a'matrix formed from polyamide polymer and fibrils ofpolyester polymer, said fibrils being largely of a diameter less than2.5 microns and having a length greater than 5 microns, said polyblendfibers being drawn after extrusion to cause the fibrils to alignthemselves in the direction of the principal axis of the fiber, and thefibers being substantially aligned with one another prior to their beingblended into a cohesive mass, said fibers being aligned and compressedby winding on a reel to form a mass of fibers, which is fused togetherat a temperature of about 250C. for 30 to minutes to cause saidpolyamide polymer matrix to blend into a cohesive union between adjacentfibers, cooling the mass to room temperature, and cutting and formingthe mass into a cabachon with the fibrils running generally parallel tothe base of the cabachon, whereby the cabachon exhibits chatoyancy.

2. The method of claim 1 wherein the polyester fibrils have a diameterless than 0.72 microns.

2. The method of claim 1 wherein the polyester fibrils have a diameterless than 0.72 microns.